Floating roof



March 6, '1 956 Filed Jan. 15, 1953 R. c. ULM r 2,737,310 I FLOATING ROOF 2 Sheets-Sheet 1 Inventor Re'gn C. Ulm

March 6, 1956 R. c. ULMV 2,737,310

FLOATING ROOF" Filed Jan. 15, 1955 2 Sheets-Sheet g FR T T I 55 1 23 2 3111 IIA DP 555555-5551? I? ii-i?ff 5 fi l7 Inventor K R 9n C. Ulm

United States Patent C) FLOATING ROOF Reign C. Ulm, Schererville, Ind., assignor to Graver Tank & Mfg. Co. Inc., East Chicago, Ind., a corporation of Delaware Application January 15, 1953, Serial No. 331,413

1 Claim. (Cl. 220-26) This invention relates to improvements in the seal mechanism for a floating roof, as used for the protection of volatile products such as gasoline. This is a continuation in part of my copending application S. N. 319,806, now Patent No. 2,650,738, issued September 1, 1953.

Said earlier application has disclosed a combined seal shoe supporting and seal action maintaining mechanism, utilizing a resiliently extensible arm which pivotally interconnects a lower part of the floating roof with an upper part of the seal shoe. Such an arm furnishes adequate support for the seal shoe; and since it is resiliently extensible it efliciently and economically avoids certain distortions'of the seal shoe, as explained in my earlier application. The arm can be formed very simply by telescoping pipes, resiliently extended by a coaxially arranged compression spring, and terminally pivoted. In said earlier application the arm has been shown in that form.

I have discovered that further improvement is possible by interposing at least one of the required pivots between a resiliently extensible part and the arm itself, rather than vice versa. In this new and preferred arrangement, an angle (of variable magnitude) is formed between the arm and the spring or equivalent device. Theoretically, such an angular arrangement seems unnecessary and odd; however, in practice it has definite advantages. This applies mainly, but not exclusively, if the spring is interposed between the lower, inner end of the arm and the floating roof.

It is a basic object of this application to secure these further advantages.

A particular object and feature is, separation of the rigid arm from the resilient spring or equivalent device, in order that each can be constructed of materials most suitable for its particular functions. Both efficiency and economy are thus enhanced. 1

Another particular object and feature is, improved lubrication of the extensible or slidable parts. This leads to a longer and more successful life for such parts.

These and other features will be understood more clearly from the description of preferred embodiments, which follows.

In the drawing:

Figure 1 is a partial cross-sectional view of a floating roof utilizing the present invention.

Figure 2 is an enlarged detail from Figure 1.

Figure 3 is another view of the detail of Figure 2, the view being taken along lines 3-3 of Figure 2.

Figure 4 is another enlarged detail from Figure 1; and Figure 5 is a view generally similar to Figure 1, showing a slight modification of the apparatus of that figure.

Referring first to Figures 1 to 4:

The floating roof FR floats on the liquid level LL of the product P stored within the tank shell TS. The rim plate RP of the floating roof FR is separated from the inside of the tank shell TS by a peripheral space PS in order to avoid frictional interference between metallic members TS and RP, while allowing the tank shell TS to be built and operated economically, that is, without ice extreme precaution against the occurrence of out-of roundness, plate irregularities, rough seams and the like.

The bulk of product P is protected from evaporation loss by the deck plate DP of the floating roof. In order to avoid evaporation loss also in the peripheral space PS, that space is covered by a flexible seal P8 of annular shape. The inner edge of this seal is secured to the top of the rim plate RP. The outer edge has a thin, metallic seal shoe SS marginally secured thereto, which bears against the inside of the tank shell TS. Preferably said outer edge is located above the top of the rim plate RP, and the seal shoe SS extends downward to an elevation below the liquid level LL. Horizontally, the seal shoe extends around the entire floating roof FR. Usually it has one or several expansion joints, of well known construction, not shown. The number of these joints is minimized since they are expensive and relatively ineflicient for vapor sealing. As a result, the thin seal shoe SS is only horizontally flexible and vertically rigid.

The weight of the seal shoe SS and a substantial part of the flexible seal FS must be supported from the floating roof FR. This is achieved by rigid support or hanger arms or struts 10, which are suitably spaced around the floating roof and which pivotally interconnect the floating roof and seal shoe structures.

For this purpose a horizontal pivot pin 11 extends across or through the upper end 12 of each arm 10. It is pivoted in a pair of pivot clips 13 secured to an upper part of the seal shoe SS. Another pivot pin 14 is secured to the lower end 15 of the arm 10 and pivoted in a clevis 16 which is held to a lower part of the floating roof FR. The connection between the clevis 16 and the floating roof PR is vertically yielding and resilient. This is achieved by securing the clevis 16 to an upright, solid or tubular slide member 17, vertically slidable within and guided by an outer, tubular guide or slideway member 18. That member is rigidly secured to the underside of the deck plate DP by a gusset 19. A vertically oriented compression spring 20 is interposed, with a bottom end 20A rigidly bearing against the top of the guide member 18, and with a top end 20B rigidly bearing against the underside of the clevis 16. Preferably the spring coaxially surrounds the slide member 17. Excessive upward expansion of the spring 20 and loss of engagement between the members 17 and 18 is prevented by a stop plate 21, secured to the bottom end of the slide member 17 below the bottom of the guide member 18.

It is alsopossible, as shown in Figure 5, to reverse the relative positions of the rigidly attached clips 12 and the resiliently supported clips 16. In other words, a support arm 10A may be pivoted by a pin 11A to clips 13A secured to the bottom part of the floating roof FR; and the upper, outer end of the arm 10A may be pivoted to a clevis 16A resiliently secured to the seal shoe SS by a slide member 17A within a guide member 18A secured to the shoe.

The arrangement of Figure 1 has the important advantage that the relatively slidable members 17 and 18 are permanently lubricated by the product P. Also, a maximum of design flexibility is provided for the seal shoe SS. In the arrangement according to Figure 5, inspection and servicing of the slidable and spring loaded members 17A, 18A is facilitated. Both embodiments differ from those of my earlier application in that the resilient spring and slide member is separated from the rigid arm itself, so that the entire arm can be made of material best suited to its function as a strut, for instance plain, mild steel, or galvanized steel, while the spring and slide unit can be made, without excessive cost, from materials most suitable for movable devices, including stainless steel, and the like.

In operation, the local width of the peripheral space PS; atdifierent pointsthereof, is-subject to change; al though the average width of this space is kept substantially uniform. Local changes are caused for instance by rivets and' other irregularities" in the tank'- shell TS; or by wind pressure acting on the fibating'roof FR" or'tarik she'll TS or both. When such a change-takes place-the floating roof FR and'parts rigid therewith, such as sleeve 18, move alonghorizo'ntal paths H'relativeto' the shell. Arm '10- is constrained to rotate about pivot 11; therefore the lower end 15 of this arm, with pivot 14 and clevis 16, moves in a circular are C relative to the pivot 11. The vertical component of' the arcuate movement isallbwed by the resilience of the spring 20; notallowed, the upperpivot 11 with'th'e shoe SSthereon would be forced to move in "an arcabout the'pivot 14, causing a deformation of thesea'l shoe; and due to the vertical rigidity of the shoe such deformation would extend over a substantial area of the peripheral space PS, causing undesirable loss of sealing efficiency.

Such losses are eifectively'prevented b'ythe new support arm connector 17, 18, 20. Further, as shown above, the connector as well as the arm itself can remain in successful and economical serviceover an extended period of time;

I claim:

In a support arrangement for a seal shoe member for use on an upright liquid storage tank'having a shell'and a floating roof member within the tank in spaced relation to'the'shell, said shoe member surroundingthe roof member and engaging the inner periphery of the shell and providing a space between the members, the combination of resilient hanger means" located in the space If it were" between the-members and providing a flexible-connection between the members, saidresilient hanger means comprising a rigid hanger arm in general angular relation to the vertical and extending between the members, a pivot on one member connected to one end of the arm and a flexible connection between the. other end of the arm and the other member, said flexible connection constituting the only connection between the other end of the arm and said other member,v said connection com prising a guide element and an element having a substan tially vertical slot therein to slidably receive and guide the guide element, one of said elements being pivotally connected to the other end of the arm andthe other of said elements being fixedly connected to the other member, abutments on both of said elements, and a compression spring interposed between and having its opposite ends engaging the abutments to provide resilientrelative movement between the elements, whereby, the pivot,',the

hanger arm, said one element, the compression spring and the other of said elements are in operative seriesrelation' to each other.

References Cited in the file ofthis patent UNITED STATES PATENTS 1,673,984 Kuhl June 19, 1928' 2,148,811 Griflin Feb: 28, 1939 2,478,422 Plummer Aug. 9, 1949 2,542,444 Wilkin Feb. 20; 1951 2,576,136 Moyer Nov. 27, 1951 2,587,508 Moyer et al Feb. 26, 1952 2,696,930 Moyer Dec. 14,- 1954 

